This is a clinical trial to determine if l-deprenyl can maintain or improve function in community dwelling elderly. The specific aims are to identify a population at-risk to deteriorate cognitively and functionally; to conduct a double-blind parallel- design placebo controlled clinical trial of l-deprenyl; and to assess meaningful outcome measures including progression to dementia and loss of independence in daily activities. The WHICAP project currently assesses residents in the North Manhattan area. Based on the WHICAP evaluation, those who demonstrate cognitive deficits and functional impairments will be asked to participate. Both Spanish and English speaking elderly will be invited to participate. Patients will complete informed consent. Screening and follow-up evaluation will be conducted at the general clinical research center or in the community when necessary. Patients (N=150) will be randomly assigned to one of two conditions; l-deprenyl (10 mgs. per day) or placebo. Assessment will be completed at three month intervals for one year and will include measures of functional independence, assessment of activities of daily living, and quality of life assessments. In addition, brief neuropsychological assessments will also be completed. Parametric and non- parametric techniques will be used to assess drug effect. Endpoint analysis will use progression to dementia and functional independence measures.